Improve the output of "pub deps".

lib/src/command/deps.dart

Index: lib/src/command/deps.dart
diff --git a/lib/src/command/deps.dart b/lib/src/command/deps.dart
index 7b1bafc8a591ac080a11fd70144b8e6be77dafbd..88d570493f197f0a5653afaefcc4839d3bc3f551 100644
--- a/lib/src/command/deps.dart
+++ b/lib/src/command/deps.dart
@@ -141,7 +141,7 @@ class DepsCommand extends PubCommand {
     // being added to the tree, and the parent map that will receive that
     // package.
     var toWalk = new Queue<Pair<Package, Map>>();
-    var visited = new Set<String>();
+    var visited = new Set<String>.from([entrypoint.root.name]);
 
     // Start with the root dependencies.
     var packageTree = {};